... Size: 1/4''-1-1/2'', M3 - M42 DIN557 Steel Square Nuts Standard: ASME/ANSI B18.2.2; DIN557, DIN562Size: 1 ... . A; CL4, 5, 6, 8 Thread: M, UNC, UNF Finish: Plain, Zinc Plated(Clear/Blue/Yellow/Black), Black oxide, Nickel, Chrome ... more information, you are welcome to contact us. DIN557 Steel Square Nuts